[PATCH v6 11/14] KVM/nVMX: Use kvm_vcpu_map for accessing the shadow VMCS

[KarimAllah Ahmed]

Use kvm_vcpu_map for accessing the shadow VMCS since using
kvm_vcpu_gpa_to_page() and kmap() will only work for guest memory that has
a "struct page".

Signed-off-by: KarimAllah Ahmed <karah...@amazon.de>
Reviewed-by: Konrad Rzessutek Wilk <konrad.w...@oracle.com>
---
v4 -> v5:
- unmap with dirty flag
---
 arch/x86/kvm/vmx/nested.c | 25 ++++++++++++-------------
 1 file changed, 12 insertions(+), 13 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 53b1063..3c173b9 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -588,20 +588,20 @@ static inline bool nested_vmx_prepare_msr_bitmap(struct 
kvm_vcpu *vcpu,
 static void nested_cache_shadow_vmcs12(struct kvm_vcpu *vcpu,
                                       struct vmcs12 *vmcs12)
 {
+       struct kvm_host_map map;
        struct vmcs12 *shadow;
-       struct page *page;
 
        if (!nested_cpu_has_shadow_vmcs(vmcs12) ||
            vmcs12->vmcs_link_pointer == -1ull)
                return;
 
        shadow = get_shadow_vmcs12(vcpu);
-       page = kvm_vcpu_gpa_to_page(vcpu, vmcs12->vmcs_link_pointer);
 
-       memcpy(shadow, kmap(page), VMCS12_SIZE);
+       if (kvm_vcpu_map(vcpu, gpa_to_gfn(vmcs12->vmcs_link_pointer), &map))
+               return;
 
-       kunmap(page);
-       kvm_release_page_clean(page);
+       memcpy(shadow, map.hva, VMCS12_SIZE);
+       kvm_vcpu_unmap(vcpu, &map, false);
 }
 
 static void nested_flush_cached_shadow_vmcs12(struct kvm_vcpu *vcpu,
@@ -2637,9 +2637,9 @@ static int nested_vmx_check_vmentry_prereqs(struct 
kvm_vcpu *vcpu,
 static int nested_vmx_check_vmcs_link_ptr(struct kvm_vcpu *vcpu,
                                          struct vmcs12 *vmcs12)
 {
-       int r;
-       struct page *page;
+       int r = 0;
        struct vmcs12 *shadow;
+       struct kvm_host_map map;
 
        if (vmcs12->vmcs_link_pointer == -1ull)
                return 0;
@@ -2647,17 +2647,16 @@ static int nested_vmx_check_vmcs_link_ptr(struct 
kvm_vcpu *vcpu,
        if (!page_address_valid(vcpu, vmcs12->vmcs_link_pointer))
                return -EINVAL;
 
-       page = kvm_vcpu_gpa_to_page(vcpu, vmcs12->vmcs_link_pointer);
-       if (is_error_page(page))
+       if (kvm_vcpu_map(vcpu, gpa_to_gfn(vmcs12->vmcs_link_pointer), &map))
                return -EINVAL;
 
-       r = 0;
-       shadow = kmap(page);
+       shadow = map.hva;
+
        if (shadow->hdr.revision_id != VMCS12_REVISION ||
            shadow->hdr.shadow_vmcs != nested_cpu_has_shadow_vmcs(vmcs12))
                r = -EINVAL;
-       kunmap(page);
-       kvm_release_page_clean(page);
+
+       kvm_vcpu_unmap(vcpu, &map, false);
        return r;
 }
 
-- 
2.7.4